The Dewoitine D.520 was arguably the best fighter available to the French at the time of the Battle of France concerning World War 2.

The Dewoitine D.520 was a single seat piston-engine fighter designed and built for the French Air Force. Developed from lessons learned in their ill-fated D.513 design, Dewoitine produced a fighter of sleek design and acceptable capability, especially when compared to that of the German Luftwaffe - to which the D.520 squared off valiantly yet unsuccessfully in the Fall of France in 1940. Despite this, the D.520 was generally respected and use continued by the Vichy French Air Force and even in post-war France. The D.520 signified France's first successful and best "modern" fighter design of World War 2.

Design work on the D.520 began as early as 1936, with the first prototypes flying by 1938. Beyond some design modifications and differing engine types (all from the Hispano-Suiza line) the models varied little. From the D520.1 prototype, the base D.520 series was born and ordered up for production by 1939, with the system being fielded by 1940 - to which only some 36 had actually been delivered when the Germans invaded. The D.520 reportedly squared up well against its German counterparts though success in the defense of France was not to be. Some 114 enemy kills were made at a loss of 85 French D.520's before the eventual collapse of the aerial defense. The system stayed in production with the German-sided Vichy French Air Force and was still available in some numbers after the war.

At its core, the D.520 was a basic straight-line fighter most noted for its sleek overall design and set-back cockpit of which was enclosed canopy. The position of the cockpit so far away from the nose undoubtedly took away from the pilots visibility forward and down but the added room in the nose made for an easier engine (which featured a variable-pitch propeller system) and armament installation. Armament consisted of a nose-mounted 20mm cannon and 4 x 7.5mm machine guns, with two machine guns per wing leading edge. Trailing edge flaps were also instituted into the wing design. A single vertical tail surface adorned the empennage and retractable landing gears rounded out the features.